The purpose of this project is to examine the manner in which immunological mechanisms may contribute to diseases of the central nervous system (CNS) in humans. These studies included examination of the cellular immune response to viruses which can commonly infect the CNS and which may be related to the induction of immunopathological processes of the nervous system. In addition, these studies have examined the immune response, and in particular, the cellular immune response to antigens of the nervous system such as myelin basic protein and proteolipid protein which may contribute to autoimmune disease. The emphasis in these studies has been on identifying differences which may occur in patients with diseases of the CNS, such as multiple sclerosis, as compared to healthy individuals. Particular attention has been paid to the influence of genetic makeup on both the induction and effector phases of the immune response to viruses, as well as antigens of the CNS. Focus has been placed on identification of cytotoxic T cells specific for both viruses or antigens of the nervous system.